Japanese Patent Application Laid-Open Publication No. H11-14893 discloses horizontal movement type binoculars including: a click plate having a click portion provided in at least one part and being slidable in a direction orthogonal to a direction of an optical axis along a fixed body; an interpupillary distance click spring fitted to a movable body slidably movable in the direction orthogonal to the direction of the optical axis with respect to the fixed body and being capable of engaging with the click portion; and a lock mechanism being capable of locking and unlocking the click plate in an arbitrary position.
According to the conventional horizontal movement type binoculars, a position of the interpupillary distance at which a sense of clicking is obtained can be arbitrarily set and, besides, can be changed without canceling this set position.